<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>

<body>
  <div id="app">
    <h2>当前计数：{{counter}}</h2>
    <!-- <button v-on:click="counter++">+</button>
        <button v-on:click="counter--">-</button> -->
    <button v-on:click="add">+</button>
    <button @click="sub">-</button>
  </div>


  <script src="../js/vue.js"></script>
  <script>
    const app = new Vue({
      el: '#app',
      data: {
        counter: 0
      },
      methods: {
        add: function () {
          // console.log("add");
          this.counter++
        },
        sub: function () {
          // console.log("sub");
          this.counter--
        }
      }
    })
  </script>

</body>

</html>